Setting the record straight on calcium supplementation

Risk Management

Remember when I said that the debate over calcium was far from over?

Well, just as I predicted, the saga continues.

It’s time to set the record straight on calcium supplementation, once again. There are so many conflicting stories out there that I think it’s important to tackle this issue one more time, for safety’s sake.

First, though, a little background: Calcium is a vitally important mineral and it’s one of the most abundant in your body. It’s also tightly regulated. Low levels are a problem for a lot of reasons–most notably, higher risk of fractures and bone loss.

This is why so many people–especially women–take a calcium supplement. But in recent years, the wisdom of this decision has been called into question.

Several studies have shown that calcium supplementation could lead to a higher risk of ischemic heart disease and stroke–while other published research has refuted those claims.

So what’s a girl to do?

The study I want to tell you about today involved nearly 61,500 Swedish women. Researchers wanted to find out whether long-term calcium intake–through both diet and supplements–has any links to all-cause or heart-related mortality.

The women were divided into categories according to average total calcium intakes. The lowest intake came in at 572 mg per day, while the highest was 2,137 mg per day.

Researchers followed up on the women for an average of 19 years.

As it turns out, there’s a window of safe calcium intake. And being on the wrong side of it–in either direction–could be deadly.

Women with dietary calcium intakes higher than 1,400 mg per day were at the highest risk of all-cause mortality and death from heart disease. (But not from stroke.) And mortality rates also increased among women with dietary intakes below 600 mg per day.

Calcium supplements weren’t independently linked with heart disease death. But women with dietary calcium intakes above 1,400 mg per day who also took supplements suffered from a higher mortality rate than women who consumed the same amount of calcium without taking supplements.

This association appeared in a dose-dependent fashion. Which means that the more supplemental calcium this group of women took, the higher their risk for death.

So there you have it. High calcium intake does appear to be linked with higher risk of death–from heart disease or any cause. But as this study shows, there isn’t really a clear-cut formula for minimizing risk and maximizing benefit where calcium supplements are concerned.

Total intakes between 600 and 1,400 mg per day appear to be perfectly safe. But obviously, it’s important to consider how much calcium you’re getting from dietary sources as well.

So I’m going to stick with my usual recommendation for female patients: 500 mg of calcium in tablet form per day.

For most women, this dosage is just enough to keep you well within the safe zone.

“Long term calcium intake and rates of all cause and cardiovascular mortality: community based prospective longitudinal cohort study.” BMJ. 2013 Feb 12;346:f228. doi: 10.1136/bmj.f228.